1. Technical Field
The present invention relates to a liquid ejecting head that ejects a liquid from nozzle orifices, a method of producing the liquid ejecting head, and a liquid ejecting apparatus, and in particular, to an ink jet recording head that discharges ink as a liquid, a method of producing the ink jet recording head, and an ink jet recording apparatus.
2. Related Art
Various types of ink jet recording heads, which are liquid ejecting heads used for printers, facsimile machines, copy machines, or the like utilizing a mechanism for discharging ink droplets are known. In an example of such an ink jet recording head, a part of each of pressure-generating chambers communicating with nozzle orifices is composed of a diaphragm, and the shape of this diaphragm is changed by a displacement of piezoelectric elements, thereby expanding or contracting the volume of the pressure-generating chambers. Thus, droplets are discharged from the nozzle orifices. In another example of such an ink jet recording head, the shape of a diaphragm is changed by utilizing an electrostatic force, thereby changing the volume of pressure-generating chambers. Thus, droplets are discharged from the nozzle orifices.
In a known method of producing such an ink jet recording head, for example, pressure-generating elements such as piezoelectric elements are formed on a surface of a channel-forming substrate composed of a single-crystal silicon substrate, with a diaphragm therebetween. Anisotropic etching is then performed from the side of another surface of the channel-forming substrate to the diaphragm, thereby forming pressure-generating chambers and the like.
Examples of such an ink jet recording head and a production method thereof include a structure in which a recess having a width larger than the width of a pressure-generating chamber is formed on an area of a diaphragm, the area facing the pressure-generating chamber, by anisotropic etching (for example, see JP-A-11-227190, p. 5 and FIG. 5), a structure in which a recess that has a width larger than or smaller than the width of a pressure-generating chamber and that has round-shaped corners is formed on a diaphragm (for example, see JP-A-2004-209874, pp. 5 to 7 and FIGS. 2 to 5), and a structure in which a recess or a protrusion is provided at the side of a diaphragm of partition walls constituting a pressure-generating chamber (for example, Japanese Patent No. 3713921, pp. 7 to 10 and FIGS. 1 and 3).
However, in the structure in which a recess having a width larger than the width of a pressure-generating chamber is formed on a diaphragm, the area where partition walls are in contact with the diaphragm is decreased, thereby decreasing the adhesion area. This structure causes a problem of decreasing the adhesive force between the partition walls and the diaphragm which counters the reactive force of ink during discharge of the ink. This structure is also disadvantageous in that the diaphragm may be separated from the partition walls when the driving of piezoelectric elements is repeatedly performed, and breakages, such as cracks, may be generated in the diaphragm in the boundary portions between the partition walls and the pressure-generating chamber.
When a recess having a width smaller than that of a pressure-generating chamber is formed on a diaphragm, displacement characteristics cannot be improved by controlling the thickness of the diaphragm, and displacement characteristics of the diaphragm cannot be uniform because of variations in the width of the recess.
These problems similarly occur not only in ink jet recording heads that discharge ink but also in liquid ejecting heads that eject a liquid other than ink.